1. Technical Field
The present invention relates to LED package technology, particularly to an aluminum alloy material and a method of manufacturing aluminum alloy backboard.
2. Description of Related Art
Light Emitting Diode (LED) is a semiconductor solid light emitting device, which utilizes semiconductor PN junction as the illuminant material to directly transform electricity into light. When a forward voltage is applied to both ends of the PN junction, the minority carriers and the majority carriers injected into the PN junction are recombined so as to release excessive energy and lead to photon emission, thereby emitting light with red, orange, yellow, green, cyan, blue or purple colors. LED light source, having the advantages of low energy consumption, long service life, environmental friendly and others, has become a hot research topic and is widely used in lighting equipments, and is regarded as the next generation light source.
LEDs are categorized into high-power LEDs and low-power LEDs according to the power supply. Generally, the nominal current of a low-power LED is 200 mA; those LEDs having a nominal current higher than 200 mA are basically considered as high-power LEDs.
High-power LED chips used for illumination generate large quantity of heat during use. Failure to duly disperse the heat will lead to unstable light output and severely affect the service life of the LED chips. In order to prolong the service life, LED chips are usually packaged on a backboard, which helps to disperse the heat generated during use. Meanwhile, a backboard is usually made of metal or alloy having excellent heat-conducting properties to improve the heat dissipation performance of the backboard. A lighting equipment is produced by welding the backside of an LED chip to a backboard.
Current backboards are made of materials as aluminum, aluminum alloy or copper. However, aluminum has poor heat-conducting properties, the thermal conductivity of which is only about 92 W/m or lower. Although copper has good heat-conducting properties, the disadvantages of using copper to produce backboards are severe distortion and high cost.
As for aluminum alloy, current aluminum alloy is usually ordinary industrial aluminum alloy, the ingredient of which mainly comprises Al, Si, Mg, Cu, etc., wherein the contents of Si and Mg arc pretty high, as a result, the heat-conducting property of the aluminum alloy is poor. the thermal conductivity being no higher than 92 W/m, and the aluminum alloy is easy to distort after heated. Furthermore, forging is generally used as the method of manufacturing industrial aluminum alloy backboard.
Forging is a manufacturing process that imposes pressure on solid metal by using a forge press machine to cause plastic deformation of the solid metal so as to form forge pieces with certain mechanical property, certain shape and size. Since a forging process does not involve the step of melting, it is not easy to dope impurities into the material during the process; therefore, forging is mainly used to manufacture boards. For aluminum alloy, one needs to firstly prepare a solid aluminum alloy material, and then impose pressure on the solid aluminum alloy by using a forge press machine to cause plastic deformation of the solid aluminum alloy so as to form an aluminum alloy backboard with certain mechanical property, certain shape and certain size. The disadvantage of forging is low utilization rate of material, and boards might also be cracked during the process, so that the manufacturing cost of forging is rather high.
Therefore, it is necessary to improve the existing backboard material and the existing method of manufacturing backboard.